131 



X. erassa, Hinds, its nearest ally in recent creation, from which. 

 it differs in its depressed elongated shape. 



Leda apiculata, spec. nov. PI. ix., figs. 4a— 4&. 



Shell ovate-subtrigonal, ventricose, inequilateral ; umbo 

 moderately inflated, rounded, recurved, in the anterior half. 

 Anterior side inflated, rounded ; ventral border arched, pos- 

 terior side shortly acuminately rostrated ; antero-dorsal margin 

 sloping, post-dorsal area depressed, slightly elevated at the 

 end. Whole surface marked with concentric raised threads 

 narrower than the interspaces. Lunule well defined, striated ; 

 cardinal teeth about fifteen on each side of a small triangular 

 ligamental pit. 



Dimensions of figured specimen. — Length, 9'5 ; height, 5'5 ; 

 thickness, 4 millimetres ; of a larger example the longitudinal 

 and transverse diameters are IL and 65 millimetres re- 

 spectively. 



Localiiies. — Abundant in the Turritella clays at Blanche 

 Point, Aldinga Bay ; also in the glauconite sands, Adelaide 

 bore ; Muddy Creek and Schnapper Point, Yictoria. 



Leda leptorhyncha, spec. nov. PI. x., figs. 5a — 5&. 



Shell minute pyriform, subventricose, much inflated in the 

 middle ; umbos subcentral, slighty elevated and recurved. 

 Anterior side rounded, with the dorsal margin sloped ; ventral 

 border arched very abruptly sloping upwards posteriorly ; pos- 

 terior side a little the longer, much compressed , and acuminately 

 rostrated above. Surface marked with concentric ridges and 

 strise, more or less obsolete on the beak. Lunule narrow lan- 

 ceolate. Cardinal teeth, about 15 on each side of a small but 

 well-defined triangular cartilage pit. 



Dimensions. — Length, 5 ; height, 3 ; thickness through both 

 valves, 2 millimetres. 



Localities. — Turritella marls, Aldinga Bay ; glauconite 

 sands, Adelaide bore. Very common. 



This species is not the young of L. apiculata, from which it 

 differs by the contraction and compression beneath the rostrum, 

 by its irregular sculpturing, and by its shape. Examples of 

 L. apiculata of the size of the present species differ from the 

 adult only by the post-dorsal side being straight, not elevated 

 at the end, 



Leda lucida, Tenison-Woods. PL vi., figs, la — Ih. 



Reference. — Proc. Linnean Soc, N.S.W., vol. iv., p. 3, t. 1, 

 fig. 5 (1879). 



Shell thick oblong, subventricose, umbo almost central, de- 

 pressed, very slightly recurved j dorsal margin sloping an- 



